6204/11-1

General

The main objectives for well 6204/11-1 was to test commercial reserves of hydrocarbons in sandstones of Middle Jurassic age and in sandstones of Turonian age. A secondary objective was to test the play concept and possibly prove hydrocarbons in an Upper Jurassic sandstone.

Operations and results

Well 6204/11-1 was spudded on 10 October 1994 with the semi-submersible rig "Deepsea Bergen" and drilled to 2966 m in the Triassic Grey Beds. The 30", 20" and 13 3/8" casings strings were successfully set. The 9 5/8" casing was planned but left out. The 12 1/4" hole was drilled using a packed bottom hole assembly. The vertical hole was obtained at high weight on bit and reduced bottom hole assembly failures due to shock / vibration effects. No drilling problems were encountered. The well was drilled with pre-hydrated bentonite (PHB) to 540 m, and KCl polymer mud from there to TD.

The well proved, with some exception, the geological model. Sandstones of both Upper and Middle Jurassic age were encountered. The well was however terminated in Triassic sediments not in the basement as prognosed.

The well proved hydrocarbons with low saturation from 2029 to 2046 m in sandstone of Turonian age. The top of the Jurassic prospect was penetrated 23 m deeper than prognosed and proved to be gas bearing. The gas-water contact was found at 2792.5 m TVD RKB (2769.5 m TVD MSL). Good oil shows were observed in the cores below the gas-water contact and measurements from the cores indicate immature oil with low saturation below the gas - water contact.

Six cores were cut, three in the Cretaceous and three in the Jurassic. FMT and RCI wire line samples were taken at 1938 m (gas and mud filtrate), 2032.5 m (mud filtrate and small amounts of oil), 2043.8 m (mud, mud filtrate, and oil film), and 2787 m (mud filtrate and gas).

The well was plugged and abandoned on 14 November 1994 as as a gas discovery.

Testing

No drill stem te